| Company | Siemens Windpower/ABB |
| Location | United Kingdom |
| Date | 2010-2013 |
| Project Overview | Siemens Windpower/ABB retrofitted a rural distribution substation (typically 11–33kV, 500–1,000 kVA range) with MIDEL 7131 and MIDEL EN 1204 ester fluids. |
| Products | MIDEL Synthetic Ester, MIDEL Natural Ester |
Off the east coast of the UK, in the outer Thames Estuary, the Greater Gabbard Offshore Wind Farm stands as one of the world’s landmark renewable energy projects. At the time of commissioning, it was the largest offshore wind farm globally, with 140 turbines generating clean power from the sea.
Each turbine needed a reliable and safe way to handle electrical conversion inside the tower. For this, MIDEL transformer fluid played a key role in ensuring safe and efficient operation in a challenging offshore environment.
Offshore wind turbines face extreme conditions—salt air, limited space, and strict safety requirements. Inside each turbine tower, transformers must operate reliably while managing high temperatures and confined installation areas.
Mineral oil was not suitable because of fire safety risks, especially inside turbine towers where emergency response is limited. Other alternatives, such as cast resin or conventional fluid-filled designs, could not meet the cooling and design requirements of the system.
The project needed a solution that was both safe and capable of handling high performance demands in a compact space.
The solution was a 3.6 MW Siemens SWT3.6-107 turbine design that used MIDEL-filled transformers installed within the transition piece of the tower.
MIDEL ester fluid was selected because it is fire safe, environmentally friendly, and well suited for high-temperature operation. The design used a fluid-cooled system with heat managed through a remote cooling arrangement in the high-voltage duct.
ABB Waterford manufactured the transformers, drawing on their experience with MIDEL distribution units. During design and installation, the MIDEL technical team supported ABB with guidance on fluid handling and insulation impregnation to ensure reliable performance.
Using MIDEL allowed the project to safely install transformers inside turbine towers without the fire risks associated with mineral oil.
The fluid’s high fire safety classification improved overall turbine safety, particularly important in offshore environments where access is limited.
Its strong thermal performance supported efficient cooling in a compact design, enabling reliable long-term operation.
MIDEL also provided environmental benefits, supporting the project’s broader sustainability goals.
The Greater Gabbard Wind Farm was successfully completed and fully operational by 2012, delivering large-scale renewable energy to the UK grid.
The MIDEL-filled transformers have performed reliably in offshore conditions, supporting continuous turbine operation since commissioning.
The success of the project reinforced MIDEL’s role as a trusted solution for offshore wind applications, where safety, performance, and environmental protection are all critical.